A criminology professor was charged with wildfire arson in California. The crime is far more common than you think.

• Gary Maynard, a criminology professor, was recently charged with willfully setting fire to US-owned land.
• In California, 9% of wildfires are caused by arson, officials say.
• Arson is becoming a more dangerous crime as rising temperatures lead to larger, more devastating fires.

The strange case of a former criminology professor charged with setting a beloved California forest on fire is shining a light on an overlooked cause of wildfires in the state: arson.

In July, Gary Maynard, age 47, was apprehended by a US forest service investigator who was responding to a wildfire on Mount Shasta, in northern California. According to court documents, the investigator found Maynard trying to free his car, which he'd gotten stuck on a boulder. Tire tracks from Maynard's car later matched tracks discovered near a second wildfire that began in the area less than 24 hours later.

"After visiting the scene and examining the area, I concurred that the ignition of this fire was not only suspicious, but once again consistent with arson," the investigator explained in the documents.

Maynard is awaiting his hearing in a Sacramento jail, according to The New York Times. A scholar who taught classes about deviance and criminality at various colleges, including Santa Clara, Chapman, and Sonoma State Universities, Maynard is charged with "willfully setting fire to land owned by or under the jurisdiction of the United States."

That crime may seem like an anomaly, but wildfire arson is surprisingly common. In California, 9% of wildfires are linked to arson, according to a report by the state's Department of Forestry and Fire Protection.

Between 2010 and 2019, arson was linked to more than 2,000 wildfires, the Cal Fire report said. During the same time period, 20% of California wildfire sources were classified as "undetermined," while the most prevalent known sources were equipment use like welding or hot exhaust (12%), and vehicle-related causes such as exhaust and collisions (also 12%). Fires related to electrical power and power lines were close behind (10%).

Intentional or not, people start most wildfires

A 2017 study analyzed US government records of wildfires between 1992 and 2012, and found that 84% of the country's wildfires were started by people, though often by accident.

The human-started fire category includes blazes ignited by cigarettes, errant sparks from equipment, campfires, burning debris, fireworks, downed power lines, and arson. This year's Dixie Fire, which began in July and has burned more than 900,000 acres, is believed to have started after a tree fell on a power line. In aggregate, that human activity has tripled the length of fire season compared to wildfires started by natural causes like lightning. The area those fires have damaged is seven times larger than that from lightning fires, the researchers found.

For a spark to become a full-blown wildfire, a combination of factors, including dryness and wind, need to align. But as rising temperatures cause soil and brush to dry out, swaths of US forests, particularly in the West, are more vulnerable than ever. Drought conditions are more widespread and severe in the Southwest and West than they've been in 20 years, Insider reported earlier this summer.

Rising temperatures in California also mean fire season now starts earlier and ends later each year, due in part to shrinking snow packs, which trigger an earlier spring melt and overall drier drought seasons, according to the National Oceanic and Atmospheric Administration. That makes arson a far more dangerous crime than it was in the past.

In addition to fires' environmental damage on the ground and in the atmosphere, wildfire smoke takes a toll on human health. When massive wildfires ripped through Oregon, California, and Canada this summer, skies darkened thousands of miles away - triggering air quality warnings as far as New York and Boston.

Smokey air can trigger immediate problems, like coughing, trouble breathing, chest pain, and asthma attacks. But there are potential long-term effects of wildfire smoke exposure, too. Microscopic particles from wildfire smoke that penetrate the lungs have been linked to chronic heart and lung diseases and even premature death.

During the pandemic, the health risks of smoke were magnified, according to a study published in August. The researchers analyzed data from 92 counties in California, Oregon, and Washington during 2020 and found strong evidence that short-term exposure to fine particulate matter from wildfire smoke was linked to more COVID-19 cases and deaths than would have occurred otherwise. An earlier study also suggested that air pollution could accelerate the coronavirus' spread.